/**
 * Copyright SunEEE Limited (c) 2015. All rights reserved.
 * This software is proprietary to and embodies the confidential
 * technology of SunEEE Limited.  Possession, use, or copying
 * of this software and media is authorized only pursuant to a
 * valid written license from SunEEE or an authorized sublicensor.
 */
package com.base.core.util;

import com.base.core.error.ErrorUtils;

import java.security.Key;
import java.security.Security;

import javax.crypto.Cipher;



/**
 * ZhiLi:     Change to the actual description of this class
 * @version   Revision History
 * <pre>
 * Author     Version       Date        Changes
 * ZhiLi      1.0           2015年1月7日     Created
 *
 * </pre>
 * @since B2B1.0.0
 */

public class DESUtils {

    private static String strDefaultKey = "suneee";

    private Cipher encryptCipher = null;

    private Cipher decryptCipher = null;

    private static final DESUtils bean = new DESUtils();

    public static DESUtils getInstance() {
        return bean;
    }

    private static String byteArr2HexStr(byte[] arrB) throws Exception {
        int iLen = arrB.length;
        // 每个byte用两个字符才能表示，所以字符串的长度是数组长度的两倍 
        StringBuffer sb = new StringBuffer(iLen * 2);
        for (int i = 0; i < iLen; i++) {
            int intTmp = arrB[i];
            // 把负数转换为正数 
            while (intTmp < 0) {
                intTmp = intTmp + 256;
            }
            // 小于0F的数需要在前面补0 
            if (intTmp < 16) {
                sb.append("0");
            }
            sb.append(Integer.toString(intTmp, 16));
        }
        return sb.toString();
    }

    private static byte[] hexStr2ByteArr(String strIn) throws Exception {
        byte[] arrB = strIn.getBytes();
        int iLen = arrB.length;

        // 两个字符表示一个字节，所以字节数组长度是字符串长度除以2 
        byte[] arrOut = new byte[iLen / 2];
        for (int i = 0; i < iLen; i = i + 2) {
            String strTmp = new String(arrB, i, 2);
            arrOut[i / 2] = (byte) Integer.parseInt(strTmp, 16);
        }
        return arrOut;
    }

    public DESUtils() {
        this(strDefaultKey);
    }

    public DESUtils(String strKey) {
        try {
            Security.addProvider(new com.sun.crypto.provider.SunJCE());
            Key key = getKey(strKey.getBytes());

            encryptCipher = Cipher.getInstance("DES");
            encryptCipher.init(Cipher.ENCRYPT_MODE, key);

            decryptCipher = Cipher.getInstance("DES");
            decryptCipher.init(Cipher.DECRYPT_MODE, key);
        } catch (Exception e) {
            throw ErrorUtils.wrap(e);
        }
    }

    private byte[] encrypt(byte[] arrB) throws Exception {
        return encryptCipher.doFinal(arrB);
    }

    public String encrypt(String strIn) throws Exception {
        return byteArr2HexStr(encrypt(strIn.getBytes()));
    }

    private byte[] decrypt(byte[] arrB) throws Exception {
        return decryptCipher.doFinal(arrB);
    }

    public String decrypt(String strIn) throws Exception {
        return new String(decrypt(hexStr2ByteArr(strIn)));
    }

    private Key getKey(byte[] arrBTmp) throws Exception {
        byte[] arrB = new byte[8];
        for (int i = 0; i < arrBTmp.length && i < arrB.length; i++) {
            arrB[i] = arrBTmp[i];
        }
        Key key = new javax.crypto.spec.SecretKeySpec(arrB, "DES");
        return key;
    }

    public static void main(String[] args) {
        try {
            String test = "zhili@suneee.com";
            DESUtils des = new DESUtils();//默认密钥 
            System.out.println("加密前的字符：" + test);
            System.out.println("加密后的字符：" + des.encrypt(test));
            System.out.println("解密后的字符：" + des.decrypt(des.encrypt(test)));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
